It's pretty much a preference in this case for me. I like our current forwards more than him and I wouldn't want the club to spend so much money on Sancho, who would no doubt displace Greenwood in the starting 11.
Like I said in this and other threads, I'd much rather we invest in a left-footed player, that can play from the right or instead of Bruno. Someone similar to Mata, who just can't be a regular for us anymore, it would bring balance and a different kind of dimension to our squad.
If we didn't have 1 of our current attacking trio, I'd be all over this guy. But as things stand, I'd rather we look at other more pressing priorities when it comes to spending huge amounts of money. It's about complimenting the squad we have and the style of football we want to play, a left-footed forward on the right will allow AWB or whoever the RB is to overlap a lot more effectively. Like I said, these are all my personal preferences. Sancho is a top player, but I don't want us to eventually lose one of Martial or Rashford, like it happened with Sane at City. I just like them too much. In my eyes, Greenwood can become even better than Sancho, could be bias, but it is what it is.